Protesters stood in front of the bus and yelled, “Set the children free” and “Shame on you” at Border Patrol officers. The Border Patrol ended up surrounding the bus so it could back up and go out the other end of the street.

Authorities didn’t say who was on the bus or where it was going, but CNN reporters could see children through the darkened windows. CNN was reaching out to federal immigration officials for comment.

One protester told CNN she also saw children through the windows. She said some of the children waved at her and she told them, “You are not alone” in Spanish.